Paul mince



UNITED STTES p PAUL MINCE, O'E HERM SDORF, UNTEIR- KYNAS'I, GERMAiNY.

PROCESS FOR PRODUCING CELLULOSE JEORMATIONS.

narrate.

No Drawing.

To all whom it may concern:

Be it known that I, PAUL MINGK, a subject of the German Emperor, King of Prussia, and a resident of Hermsdorf, 'unter Kynast, Province of Silesia, Kingdom of Prussia, German Empire, have invented new and useful Improvements in Processes for lroducing Cellulose Formations, of

caustic alkali when precipitating known to add alkali chlocontaining cellulose products or cellulose formations out of ammoniacal copperoxidcellulose solution, which addition accelerates the coagulation of the thread andallows of using a more .dilute solution of alkali (German Patent 206883).

'A spinning bath containing little sodium hydroxid passing hydroxid besides a greater quantity of sodium chlorid has a considerably greater coagulating than a pure sodium hydroxid bath. The alkali chlorid of the spinning bath expels the water from the coagulating threads so vigorously and quickly, that the molecules of the cellulose collect to form a substanceof very compact structure. Thus a very firm glossy and extremely smooth thread is formed the qualities of which predestines it for many uses especially forv producing woven goods. Said qualities are however undesirable for other purposes where products of looser structure are preferred.

A product with the latter qualities is formed if alkali carbonate, for instance soda, is added instead of alkali 'chlorid to a weak solution of caustic alkali, the percentage of carbonate being kept in .a certain proportion to the respective quantity of copper contained in the bath. In this case a reaction takes place by which the copper during the spinning into the spinning bath is transformed into copper carbonate which is. kept in solution by the caustic lye of alkali containing also ammonia (NH During the coagulation of the thread the copper hydroxid contained therein is transformed by the copper carbonate of the bath into copper subcarbonate, the ammonia being displaced at the same time by the lye. The resulting basic copper carbonate is no longer soluble in the causcopperoxidcellulose soefi'ect and is more economical Specification of Letters Patent. Y Patent gfl Sept, 3613', 19119,; Application filed September 2, 1914.. Serial no. 959,921.

The subcarbonate is however very soluble in moderately concentrated acids and is perfectly segregated by these from the thread. When removing the copper from the coagulated thread, for instance by sulfuric acid, copper sulfate is formed, while the carbondioxid is expelled from the thread. This seems to be the cause of the crystallike and yet loose results in a highly glossy product, the whole separate threads of which remain perfectly supple and pliable without gluing together. The thread is more elastic, fuller, whiter and softer and altogether improvedwhen compared with the threads already. known.

The production of such threads with the assistance of a bath of pure sodium hydroxid or of a bath containing alkali chlorid besides the hydrate, was hitherto impossible because the copper compounds forming in the thread in such bath reacted altogether otherwise. In such case the copper compounds produced, are little soluble in acids and decompose in a short time in the presence of air.

Contrary to this, the basic copper carbonate which is formed by the process of-my invention does not decompose at all, which is a considerable advantage, if the spun thread-cannot be decopperized directly, as may happen when the manufacture is interrupted for some reason or other. It is important to note that a fresh bath of sodium hydroxid and of sodium carbonate which contains no copper salts gives only a spongy, milky and inferior product, evidently because in this case the soda: cannot convert the copper hydroxid in the coagulating thread quick enough intojcarbonate'and flicts with the ammonia still contained in the thread. It is only the copper carbonate which was formed before in the bath, that constitution of the cellulose which r.

can convert the copper hydroxid in the is important to understand the cooperation of the ammoniacal copper oxid in the coagulating thread with the alkali hydrate and the copper'carbonatecontained inthe spin ning bath. By the copper carbonate turning the copper hydroxid which is soluble in ammonia into a subcarbonate which is scarcely or not at all soluble, the thread coagulates just as quickly as in the bath of sodium hydroxid and alkali chlorid, while the percentage of alkali hydroxid is in both cases equally low, a far smaller quantity of alkali carbonate than of alkali chlorid being required to. attain the same good efl'ect. My new bath is superior to the former, both with regard to economy and to a better product, especially as hydrate of alkali is formed by the reaction of copper hydroxid on alkali garllclonate which is an advantage for the Example.-

In 10,000 liters of water, 400 kilograms of sodium hydroxid and 100 kilograms sodium carbonate (equal to 4% and 1% respectively) are dissolved and then still 50 kilograms of copper hydroxid (equal to about 1}%). This latter need only be added once because during the spinning of the ammoniacal copperoxidcellulose solution a part of the copper hydroxid passes into the bath in consequence of the physical friction between the threads and the bath; this copper hydroxid is converted into copper carbonate by soda which is added during spinning in suitable quantities to the bath. Such bath allows of a spinning speed of 45 meters in the minute, though the concentration of the caustic soda is but low.

The baths are regenerated by withdrawing a part thereof from time to time leaving only the desired quantity of copper carbonr ate in the bath. The part withdrawn is regenerated by evaporation, the ammonia being recovered as usual while the copper subcarbonate which is eas1ly decomposed at boiling point is precipitated as granular salt free of water without having to use the usual means of reduction.

I claim:

1; A process for producing cellulose formations, consisting 1n projecting cuproammonium cellulose solution into a precipitating bath containing copper carbonate besides PAUL MINCK.

Witnesses:

MARTIN KLUGE, I MARGARETTE SEUFTLEBEN. 

